Friction shock absorber



Ira/622215 v 77/ flflzu eltzhe Filed Dec. 24, 1943 fax:

G. A. JOHNSON 5r AL Oct. 29, 1946.

Patented Oct. 29, 1946 UN l-T ED STATES PATENT OFF ICE i 2,410,165 I v I v FRICTION SHOCK ABSORBER George A. Johnson, Chicago, and Stacy B. Haseltine, La Grange, Ill., assignors to WLH. Miner, Inc., -Chicago, 111;, a corporation of Delaware Application December 24, 1943, Serial No. 515,518

1 This invention relates to improvementsin friction shock absorbers, especially adapted for use inconnection with railway car trucks for snubprovide a friction shock absorber, as specified in the preceding paragraph, wherein the friction elee ments are in the form of relatively slidable fric-. tion posts havinginterengagingfriction surfaces which are inclined to the -central;;longitudinal axis of the mechanism and said-postshave base flanges at opposite ends of the mechanism, formed integral with the posts and on which .theposts are adapted to rock, and wherein the spring resistance is in the form of a coil surrounding said posts bearing on said base flanges to resist tilting of the posts away from each other as they arespread apart due to the action'of the cooperating inclined 'surfa'ces'thereof, and wherein the spring is canted due to the tiltingoffthe post, thereby exerting pressure to force, said'.posts tightly together and 'provide "high frictional re; sistance in opposition to lengthwise .jmoveme nt of said posts. 1 1 1:1

Other "objects of the inven on will more clearly appear fro'm'the description andcl'aim's herein-' after following.

cation,'Figure '1 isa verticalse'ctional view of our shock absorber.

Our improved shock absorber comprises broadly two similar friction posts A and B-a-rida spring resistance C.

The 'fricti'on posts Aa'nd B: are iden tical, each post comprising a'vertically. disposed heavy plate- !0 having a cylindrical baseuportion or-member:

H eccentric thereto, and a: laterally extending annular flangev l2 projectingfromsaid base :pjortion, concentric with thevertical central axis-of;

the mechanism. The .base 7 portion l l .;is slightly- "6 Claims. (01. 267-9) eccentric with respect to the vertical centralaxis of the mechanism and said base portion H and flange l2 together form a follower plate or disc member I3 which cooperates with the spring resistance C. The peripheral cylindrical surface of the base portion ll of the plate H), which surface is indicated by M, presents a substantially vertically extending abutment wall for a purpose hereinafter described. The two posts A and B are reversely arranged, that is, the post B is inverted with respect to the position of the post A. As shown most clearly in Figure 1,'the follower plate member I3 of the post A- is located at the bottom end of the mechanism and has the friction plate In upstanding therefrom while the follower plate portion [3 of the post B is located at the upper end of the mechanism and has the friction plate 10 depending therefrom.

"The free end portion of the friction plate sec-' tion of-each post is laterally inwardly enlarged, as indicated at I 5, thereby providing a horizontal shoulder I6. As clearly shown in Figure 1, the enlarged portion 15 of the post A is at the upper end thereof, while the enlarged portion of the post B is at the lower end of the latter and the shoulders of the two posts overhang each other to engage "and-limit separation of the'posts in lengthwise direction and hold the mechanism assembled. a 'i V 1 On the inner side, the friction plate member H! of each post has flat friction surfaces l'l and l8 offset with respect toeach other, said frice tion surfaces being formed respectively on the inward enlargement l5 and the main body portion of said plate member, the friction surface H of the post A having sliding contact withthe friction surface 18 of the post Band the friction surface It of the post A having sliding contact with the friction surface I! of the post B. As clearly shown in Figure 1, the friction surfaces I1 and N3 of v.ea'ch post are inclined slightlywith respect to the central vertical 5 axis of the mechanism, that is, they are inclined to a vertical plane, the frictionsurfaces ll'and Id of the post A being inclined outwardly awayfrom' said central vertical axis in upward direction and the surfaces l1 and 18 .of the post B being inclined inwardly toward said vertical aXis.-. The

inclination of the friction surfaces of the, two

posts isthe same so that-the friction surfaces have fiatface to face contact with each other. The friction plate portion ll] of each post is reinforced on its .outer side by a longitudinal central rib l9 extending from the base portion ,H- to theiaiouter end of the frictionkplate. As shown 3 most clearly in Figure 2, the outer edge of the rib is rounded off transversely to correspond with the curvature of the cylindrical outer surface M of said base portion II and merges with the surface M, as shown in Figure 1. The rib I9 is preferably slightly inclined inwardly toward the vertical axis of the mechanism, the rib of the post A being inclined inwardly in upward direction and that of the post B being inclined inwardly in downward direction. Each post is thus, in effect, tapered toward its outer end. Each follower plate member I3 is provided with a central pocket or seat 20 adapted to receive the usual spring centering projection of the corresponding spring follower plate 2| of thetruck-spring cluster, said follower plate being shown in dotted lines in Figure 1.

The parts of the friction posts are so propore tioned that movement of the posts in lengthwise direction toward each other is positively limited by engagement of the outer end of the post B with the upper side of the base portion ll of the post A and by engagement of the outer end of the post A with the underneath side of the base portion ll of the post B.

The spring resistance C, which is in the form of a heavy coil, surrounds the posts A and B and bears at its top and bottom ends on the top and bottom follower plate members |3-i3. The spring C is under initial compression and the inner sides of the top and bottom coils bear on the vertical walls M of the base portions ll of the posts at the outer sides of said posts, that is, the inner side of the coil at the upper end of the spring bears on the wall Id of the base member l l of the post B at the left hand side of the mechanism, and the coil at the lower end of the spring bears on the wall I4 of the base member ll of the post A, at the right hand side of the mechanism, as seen in Figure 1. Inasmuch as the cylindrical base portions ll of the posts are eccentric to the vertical central axis of the spring C and the mechanism as a whole, there is a substantial clearance between the wall I4 of the base member ll of the post A and the inner side of the lower coil of the spring at the left hand side of the mechanism and between the wall [4 of the base member I I of the post B and the inner side of the upper coil of the spring at the right hand side, as seen in Figure 1.

In assembling the mechanism, the spring C is first placed over the friction plate Ill of the post A. The post B is then assembled with the other parts by inserting the friction plate IQ of the same downwardly within the coils of the spring, the posts A and B being held in tilted position away from each other, so that the enlargements l5-I5 thereof will pass each other. This tilting movement of the posts within the spring. is permitted by the clearance provided due to the taper of the ribbed portions of the posts. The parts are forced together until the shoulders |6-I6 pass each other, whereupon the shoulder of the post B will snap under the shoulder of the post A, thereby locking the posts together against lengthwise separation.

Our improved shock absorber preferably replaces one or more of the spring units of a truck spring cluster, being interposed between the usual top and bottom spring plates which cooperate with said cluster, however, several of such shock absorbing units may be employed in 'a single spring cluster replacing two or more units of the latter.

The operation of the improved shock absorber 4 is as follows: Upon the spring cluster of the truck of a railway'car being compressed between the spring follower plates of the cluster, the shock absorbing unit, which is disposed between said follower plates, is compressed therewith, thereby forcing the post B downwardly toward the post A against the resistance of the spring C. Due to inclination of the cooperating friction surfaces thereof, the'posts are forced laterally outwardly during relative lengthwise movement of the same, thereby either sliding the same laterally on their bases or causing rocking or tilting movement thereof with resulting tilting of the follower plates I l3l 3 on the spring follower plates 2 l-2l of the truck spring cluster. This sliding or tilting action being resisted by the spring C causes the friction surfaces of the posts to be pressed more tightly together. At the same time, due to the sliding or tilting of the follower plate members l3--I3, a canting action of the spring is produced which causes the coil at the lower end of the spring tobe forced laterally against the cylindrical base portion of the post A at the right hand side of the mechanism and the coil at the upper end of the spring to be forced laterally against the cylindrical base portion of the post B at the left hand side of the mechanism, thereby further pressing together the friction surface portions of said posts. During relative lengthwise movement of the posts on their friction surfaces, during compression of the mechanism, the required frictional resistance is developed to effectively snub the action of the truck springs. Upon release of the mechanism, the posts A and B are restored to the normal position shown in Figure 1 by the expansive action of the spring C, longitudinal separation of the posts being limited by engagement of the shoulders 16-16 of the posts with each other. As will be evident, frictional resistance is also had during this releasing action to effect snubbing of the truck springs during recoil.

We have herein shown and described what we now consider the preferred manner of carrying out our invention, but the same is merely illustrative and we contemplate all changes and modifications that come within the scope of the claims appended hereto. 7

We claim: 7

1. Ina friction shock absorber mechanism, the combination with a pair of relatively lengthwise slidable friction posts at diametrically opposite sides of the mechanism having interengaging friction surfaces on their inner sides inclined to the longitudinal axis of the mechanism; of a coil spring extending lengthwise .of the mechanism and surrounding said posts, said spring exerting lateral inward pressure on the posts and having shouldered engagement with the posts to oppose relative lengthwise movement thereof toward each other. 7

2. In a friction shock absorber mechanism, the combination with a pair of relatively lengthwise movable friction posts at diametrically opposite sides of the mechanism having longitudinally'extending, interengaging friction surfaces on their inner sides inclined to the longitudinal axis of the mechanism; of end followers integral with the outer end portions of said'posts, said end followers being disposed at opposite ends of the mechanism; and a coil spring surrounding said posts and bearing at opposite ends on said end followers, said spring having lateral bearing eng'agement'with said posts'at said outer end portions thereof to hold the same in engagement with each other.

3. In a friction shock absorber mechanism, the combination with upper and lower spring follower plates; of a post depending from said upper follower plate at one side of the longitudinal central axis of the mechanism, said post having a longitudinally extending friction surface on the inner side thereof inclined toward the central vertical axis of the mechanism in upward direction; a second post upstanding from said lower follower plate at the diametrically opposite side of the longitudinal central axis of the mechanism, said last named post having a friction surface on the inner side extending lengthwise thereof and engaging With and correspondingly inclined to the friction surface of said first named post; and a coil spring surrounding said posts and having engagement at its top and bottom ends with said follower plates, said spring having lateral hearing engagement with the posts at the follower plate ends thereof to hold the same in frictional engagement with each other.

4. In a friction shock absorber mechanism, the combination with a pair of relatively lengthwise slidable friction posts at diametrically opposite sides of the mechanism having interengaging friction surfaces on their inner sides inclined to the longitudinal central axis of the mechanism; of a coil spring surrounding said posts; and side abutment faces on the base portions of said posts on which the inner sides of the top and bottom end coils of the spring bear to force said posts laterally toward each other.

5. In a friction shock absorber mechanism, the combination with an upper spring follower plate;

of a. lower spring follower plate; an upper friction post depending from said upper plate; a lower friction post upstanding from said lower spring follower plate, said posts being at diametrically opposite sides of the mechanism and having longitudinally extending, interengaging friction surfaces on their inner sides inclined to the vertical; and a coil spring surrounding said posts bearing at its top and bottom ends on said upper and lower spring follower plates, said spring having the inner side of the coil at the upper end seated against spring follower plate end of the same, and the inner side of the coil at the lower end seated against the outer side of the lower post at the spring follower plate end of the same.

6. In a friction shock absorber mechanism, the combination with an upper friction post having a follower plate portion at its upper end; of a lower friction post having a follower plate portion at its lower end, said posts being at diametrically opposite sides of the mechanism, said posts being displaceable laterally outwardly away from each other, said posts having interengaging, 1ongitudinally extending friction surfaces on their inner sides inclined to the vertical; and a coil spring yieldingly opposing lateral displacement of said posts, said coil spring surrounding said posts and bearing at the top and bottom ends on said follower plates with the inner side of the upper coil thereof engaging the outer side of the upper post and the inner side of the lower coil thereof engaging the outer side of the lower post.

GEORGE A. JOHNSON. STACY ASELTINE,

the outer side of the upper post at the 

